Efficient acceleration semi-autonomous feature

ABSTRACT

A system includes a power source to generate power to propel the vehicle, and a speed sensor to detect a current speed. The system also includes a camera to detect image data corresponding to a current roadway, and a GPS sensor to detect location data corresponding to a current location of the vehicle. The system also includes an ECU. The ECU is designed to determine a target vehicle speed based on at least one of the image data or the location data. The ECU is also designed to calculate an energy-efficient acceleration pattern to accelerate the vehicle from the current speed to the target vehicle speed based on a goal to minimize energy usage of the power source. The ECU is also designed to control the power source to accelerate the vehicle from the current speed to the target vehicle speed using the energy-efficient acceleration pattern.

BACKGROUND 1. Field

The present disclosure relates to systems and methods for determiningefficient acceleration patterns of a vehicle and for controlling thevehicles to accelerate using the efficient acceleration patterns.

2. Description of the Related Art

There has been a recent push for vehicle manufacturers to improvevehicle efficiency for various reasons such as reduce carbon emissions,reduce costs of operating vehicles, increased vehicle appeal, and thelike. Multiple methods have been discovered for improving vehicleefficiency. One such method controls operation of climate controlsettings of the vehicle to reduce power consumption during vehicleacceleration. Another such method is the use of hybrid vehicles torecapture energy that is typically lost during vehicle deceleration. Dueto the complexity of vehicles, numerous options are available to furtherimprove their energy efficiency.

Often times, vehicles are most inefficient during an acceleration. Thismay be especially true when a driver is relatively aggressive. In manycases, the rate of acceleration is entirely decided by a driverregardless of any surrounding inputs. Such accelerations may occur alonga highway on-ramp, when a vehicle turns on a new road, or when a speedlimit along a current roadway increases. There are often times multipleways that a vehicle can accelerate. Some acceleration patterns may berelatively energy-efficient and some acceleration patterns may berelatively energy-inefficient.

Accordingly, it is desirable to determine energy-efficient accelerationpatterns and to control a vehicle to accelerate using theenergy-efficient acceleration patterns.

SUMMARY

Described herein is a system for controlling a vehicle to accelerateefficiently. The system includes a power source designed to generatepower to propel the vehicle, and a speed sensor designed to detect acurrent speed of the vehicle. The system also includes a camera designedto detect image data corresponding to a current roadway, and a globalpositioning system (GPS) sensor designed to detect location datacorresponding to a current location of the vehicle. The system alsoincludes an electronic control unit (ECU) coupled to the power source,the speed sensor, the camera, and the GPS sensor. The ECU is designed todetermine a target vehicle speed that is greater than the current speedof the vehicle based on at least one of the image data or the locationdata. The ECU is also designed to calculate an energy-efficientacceleration pattern to accelerate the vehicle from the current speed tothe target vehicle speed based on a goal to minimize energy usage of thepower source. The ECU is also designed to control the power source toaccelerate the vehicle from the current speed to the target vehiclespeed using the energy-efficient acceleration pattern.

Also described is a system for controlling a vehicle to accelerateefficiently. The system includes a power source designed to generatepower to propel the vehicle, and a speed sensor designed to detect acurrent speed of the vehicle. The system also includes a camera designedto detect image data corresponding to a current roadway, and a globalpositioning system (GPS) sensor designed to detect location datacorresponding to a current location of the vehicle. The system alsoincludes an input device designed to receive input data, and an outputdevice designed to output data. The system also includes an electroniccontrol unit (ECU) coupled to the power source, the speed sensor, thecamera, the GPS sensor, the input device, and the output device. The ECUis designed to predict that the vehicle is to accelerate to a targetvehicle speed based on at least one of the image data or the locationdata. The ECU is also designed to control the output device to outputdata indicating the predicted acceleration. The ECU is also designed tocontrol the input device to receive confirmation that the vehicle is toaccelerate to the target vehicle speed. The ECU is also designed tocalculate an energy-efficient acceleration pattern to accelerate thevehicle from the current speed to the target vehicle speed based on agoal to minimize energy usage of the power source. The ECU is alsodesigned to control the power source to accelerate the vehicle from thecurrent speed to the target vehicle speed using the energy-efficientacceleration pattern after the input device receives the confirmation.

Also described is a method for controlling a vehicle to accelerateefficiently. The method includes generating, by a power source, power topropel the vehicle, and detecting, by a speed sensor, a current speed ofthe vehicle. The method also includes detecting, by a camera, image datacorresponding to a current roadway, and detecting, by a globalpositioning system (GPS) sensor, location data corresponding to acurrent location of the vehicle. The method also includes determining,by an electronic control unit (ECU), a target vehicle speed that isgreater than the current speed of the vehicle based on at least one ofthe image data or the location data. The method also includescalculating, by the ECU, an energy-efficient acceleration pattern toaccelerate the vehicle from the current speed to the target vehiclespeed based on a goal to minimize energy usage of the power source. Themethod also includes controlling, by the ECU, the power source toaccelerate the vehicle from the current speed to the target vehiclespeed using the energy-efficient acceleration pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

Other systems, methods, features, and advantages of the presentinvention will be or will become apparent to one of ordinary skill inthe art upon examination of the following figures and detaileddescription. It is intended that all such additional systems, methods,features, and advantages be included within this description, be withinthe scope of the present invention, and be protected by the accompanyingclaims. Component parts shown in the drawings are not necessarily toscale, and may be exaggerated to better illustrate the importantfeatures of the present invention. In the drawings, like referencenumerals designate like parts throughout the different views, wherein:

FIG. 1 is a block diagram illustrating various components of a vehiclecapable of determining efficient vehicle speeds, determining efficientvehicle acceleration patterns, and controlling a power source toaccelerate and travel at the efficient vehicle speeds and the efficientvehicle acceleration patterns according to an embodiment of the presentinvention;

FIGS. 2A and 2B are flowcharts illustrating a method for determiningefficient vehicle speeds for a given speed limit and a given vehicleload according to an embodiment of the present invention;

FIGS. 3A and 3B are flowcharts illustrating a method for determining anefficient vehicle acceleration pattern based on a target speed and acurrent vehicle load according to an embodiment of the presentinvention; and

FIG. 4 is a drawing illustrating an exemplary use of the method of FIGS.2A and 2B and the method of FIGS. 3A and 3B by the vehicle 100 of FIG. 1according to an embodiment of the present invention.

DETAILED DESCRIPTION

The present disclosure describes systems and methods for determiningefficient acceleration patterns of a vehicle. The systems provideseveral benefits and advantages such as determining energy-efficientacceleration patterns, and controlling a vehicle to accelerate using thedetermined energy-efficient acceleration patterns. The energy-efficientacceleration patterns are acceleration patterns which utilize lessenergy than alternative acceleration patterns and, thus, the systemsprovide improved energy efficiency for vehicles. The systems provideadditional benefits such as determining efficient speeds for the vehicleto travel after the acceleration. The system may control the vehicle toaccelerate to the efficient speeds and control the vehicle to cruise atthe efficient speeds, providing the benefit of increased energyefficiency of the vehicle. The system may also advantageously detectefficiency of accelerations as the vehicle is driven and may update thecalculations of the energy-efficient acceleration patterns based onrecently detected information. This provides the advantage of increasedaccuracy of the energy-efficient acceleration patterns.

An exemplary system includes a plurality of sensors that can detect datacorresponding to a load of the vehicle (such as a mass of the vehicle, agrade of the roadway, or the like) and a speed sensor that can detect acurrent speed of the vehicle. The system also includes at least one of asensor, a network access device, or a memory (which includes map data)that can detect, receive, or retrieve data usable to determine orpredict an upcoming acceleration of the vehicle and a target speed ofthe vehicle after the acceleration. The system also includes anelectronic control unit (ECU). The ECU may analyze the detected,received, or retrieved data to predict the upcoming acceleration and topredict the target vehicle speed. The ECU may also calculate anenergy-efficient acceleration pattern and may control the power sourceof the vehicle to accelerate using the energy-efficient accelerationpattern.

Turning to FIG. 1, a vehicle 100 includes components of a system 101 forimproving efficiency of the vehicle 100. In particular, the vehicle 100and system 101 include an ECU 102, a memory 104, a global positioningsystem (GPS) sensor 106, an inertial measurement unit (IMU) sensor 108,and a network access device 110. The vehicle 100 and system 101 furtherinclude a power source 111 which may include one or more of an engine112 or a combination of a battery 114 and motor-generator 116. Thevehicle 100 and system 101 may further include a transmission 118 forapplying mechanical power from the engine 112 or the motor-generator 116to wheels to propel the vehicle 100.

The vehicle 100 and system 101 further include one or more sensorsincluding a camera 120, a load sensor 122, a grade sensor 124, a mass orweight sensor 126, a thermometer or other temperature sensor 128, analtimeter 130, a speed sensor 132, and a radio detection and ranging(radar) sensor 134. The vehicle 100 and system 101 also include an inputdevice 136 and an output device 138.

The ECU 102 may be coupled to each of the components of the vehicle 100and may include one or more processors or controllers, which may bespecifically designed for automotive systems. The functions of the ECU102 may be implemented in a single ECU or in multiple ECUs. The ECU 102may receive data from components of the vehicle 100, may makedeterminations based on the received data, and may control the operationof components based on the determinations.

In some embodiments, the vehicle 100 may be fully autonomous orsemi-autonomous. In that regard, the ECU 102 may control various aspectsof the vehicle 100 (such as steering, braking, accelerating, or thelike) to maneuver the vehicle 100 from a starting location to adestination.

The memory 104 may include any non-transitory memory known in the art.In that regard, the memory 104 may store machine-readable instructionsusable by the ECU 102 and may store other data as requested by the ECU102.

The GPS sensor 106 may be capable of detecting location datacorresponding to a location of the vehicle 100. The IMU sensor 108 maydetect a velocity or an orientation of the vehicle 100. One or both ofthe GPS sensor 106 or the IMU sensor 108 may be referred to as alocation sensor and may be used to determine a current location,heading, and/or orientation of the vehicle 100. In some embodiments, oneor both of the GPS sensor 106 or the IMU sensor 108 may be capable ofdetecting a speed of the vehicle 100 and may thus be referred to as aspeed sensor.

The speed sensor 128 may be any speed sensor capable of detecting datausable to determine a speed of the vehicle 100. For example, the speedsensor 128 may include a GPS sensor or an IMU sensor, as mentionedabove. The speed sensor 128 may also or instead include an angularvelocity sensor configured to detect an angular velocity of the wheelsof the vehicle 100 or the engine, a speedometer, or the like.

The network access device 110 may include any port or device capable ofcommunicating via a wired or wireless interface such as Wi-Fi,Bluetooth, a cellular protocol, vehicle to vehicle communications, orthe like. For example, the ECU 102 may control the network access device110 to communicate with the cloud, an external vehicle, or any otherobject or device. In particular, the network access device 110 maycommunicate directly or indirectly with another vehicle. In that regard,the network access device 110 may communicate via a vehicle to vehicle(V2V) protocol and may thus be referred to as a V2V network accessdevice. In some embodiments, the network access device 110 may transmita current vehicle speed or a current acceleration or deceleration of thevehicle 100 to nearby vehicles.

The engine 112 may convert a fuel into mechanical power. In that regard,the engine 112 may be a gasoline engine, a diesel engine, a fuel cellgenerator, or the like.

The battery 114 may store electrical energy. In some embodiments, thebattery 114 may include any one or more energy storage device includinga battery, a fly-wheel, a super-capacitor, a thermal storage device, orthe like. The motor-generator 116 may convert the electrical energystored in the battery (or generated by a fuel cell generator) intomechanical power usable by the transmission 118. The motor-generator 116may further convert mechanical power received from the transmission 118into electrical power, which may be stored in the battery 114 as energyand/or used by other components of the vehicle 100. In some embodiments,the motor-generator 116 may also or instead include a turbine or otherdevice capable of generating thrust.

The transmission 118 may be coupled to the engine 112 and themotor-generator 116. The transmission 118 may include a power splitterand may transfer mechanical power received from one or both of theengine 112 and the motor-generator 116 to wheels of the vehicle 100. Thetransmission 118 may control how much mechanical power is transferredfrom each of the engine 112 and the motor-generator 116. For example,the ECU 102 may control the transmission 118 to achieve a desired powertransfer from each of the engine 112 and the motor-generator 116. Thetransmission 118 may further transfer mechanical energy received fromone or both of the engine 112 or wheels of the vehicle 100 to themotor-generator 116 for conversion into electrical power.

Although the present discussion is related to the vehicle 100 having ahybrid power source 111, one skilled in the art will realize that avehicle may include any one or combination of an engine, a fuel cellengine, a motor-generator and a battery, or the like without departingfrom the present disclosure.

The camera 120 may include one or more camera oriented in such a manneras to be able to detect image data corresponding to an environment ofthe vehicle 100. For example, the camera 120 may be positioned on afront of the vehicle 100 and may be capable of detecting image datacorresponding to a nearby vehicle or street sign.

The load sensor 122 may include any sensor capable of detecting loaddata corresponding to a load applied to the vehicle 100. A load may bedefined as a resistance or other force or phenomenon applied to, orexperienced by, the vehicle 100 that causes the power source 111 togenerate more or less power to cause the vehicle 100 to remain at aconstant speed relative to when the load is not applied. For example, aload may include a weight or mass of the vehicle (including weight ofcargo or passengers), a grade of a roadway, and altitude of the roadway,a velocity of a headwind or a tailwind, an ambient temperature outsideof the vehicle 100, or the like. The load data detected by the loadsensor 122 may be used to determine a load applied to the vehicle 100.

In some embodiments, load data may likewise be received from the networkaccess device 110 or stored in the memory 104. For example, weatherinformation, such as a current temperature, may be received by thenetwork access device 110 via the cloud. Similarly, navigationinformation may be received from the network access device 110 or storedin the memory 104. The ECU 102 may transmit or compare the currentlocation of the vehicle 100 to the navigation information to find acurrent grade of a roadway that corresponds to the current location oran upcoming location.

The grade sensor 124 may include any sensor capable of detecting a gradeof the current roadway. For example, the grade sensor 124 may includethe IMU sensor 108 or another device capable of determining data thatcorresponds to the grade of the roadway.

The weight or mass sensor 126 may include any sensor capable ofdetecting data corresponding to a mass of the vehicle. For example, themass sensor 126 may include one or more sensor coupled to the wheels orsuspension of the vehicle 100 that can detect the current mass of thevehicle 100. As another example, the mass sensor 126 may include one ormore sensor positioned beneath a cargo compartment or a seat of thevehicle 100 that can detect the mass of an object or person located inthe cargo compartment or on the seat.

The thermometer 128 may be capable of detecting data corresponding to acurrent temperature. For example, the thermometer 128 may be locatedoutside of the vehicle 100 and detect an ambient temperature outside ofthe vehicle, may be located in an engine compartment of the vehicle 100and detect a temperature within the engine compartment, or the like.

The altimeter 130 may include any sensor or component capable ofdetecting a current altitude of the vehicle 100. In some embodiments,the altimeter 130 may detect the altitude directly or may calculate thealtitude by comparing the current location of the vehicle to a databaseof locations and corresponding altitudes.

The radar sensor 134 may include one or more radar device oriented insuch a manner as to be able to detect radar data corresponding to anenvironment of the vehicle 100. For example, the radar sensor 134 maytransmit a radar beam, receive a reflection of the radar beam, andanalyze the reflection of the radar beam to determine the presence andcharacteristics of objects in the environment of the vehicle 100, suchas a nearby vehicle. In some embodiments, the vehicle 100 may include alight imaging, detection, and ranging (LIDAR) sensor instead of, or inaddition to, the radar sensor 134. The LIDAR sensor may function in asimilar manner as the radar sensor 134 but may transmit and receivelight instead of a radar beam. The LIDAR sensor or radar sensor 134 maydetect data corresponding to traffic conditions on a current roadway,including the speed of surrounding vehicles.

The input device 136 may include any input device capable of receivinginput from a user. For example, the input device may include atouchscreen, a touchpad, a keyboard, a button, or the like. The outputdevice 138 may include any output device capable of outputting data to auser. For example, the output device may include a touchscreen, adisplay, a speaker, or the like.

The system 101 may be used to control the vehicle 100 to operate in arelatively energy efficient manner. In that regard, the ECU 102 mayreceive data from the sensors of the vehicle 100 and determine efficientvehicle speeds of the vehicle or energy-efficient acceleration patternsof the vehicle that provide improved energy efficiency based on thedetected data. The ECU 102 may also provide instructions to a driverregarding how to achieve the improved energy efficiency or may directlycontrol the power source 111 to improve the energy efficiency.

Referring now to FIGS. 2A and 2B, a method 200 for determining anefficient driving speed of a vehicle, such as the vehicle 100 of FIG. 1,is shown. In block 202, various components of the vehicle may detect orreceive data. For example, the data may include a current speed detectedby a speed sensor, image data detected by a camera, location datadetected by a GPS or IMU sensor, load data detected by one or more loadsensor, and a current speed limit of the roadway detected by a camera,stored in a memory, or received via a network access device.

In block 204, the ECU of the vehicle may determine whether the vehicleis within a steady speed range. The steady speed range indicates thatthe vehicle is moving at a relatively constant speed. The vehicle may beconsidered to be within the steady speed range when the current speed ofthe vehicle fluctuates less than a predetermined speed threshold over apredetermined time period. The predetermined speed threshold maycorrespond to a speed fluctuation that is normal during a cruising orconstant speed operation, such as two miles per hour (2 mph), 3 milesper hour, 5 miles per hour, or the like. The predetermined time periodcorresponds to an amount of time sufficiently long that the ECU mayinfer that the vehicle speed will remain constant. For example, thepredetermined time period may be 3 seconds, 5 seconds, 10 seconds, orthe like.

As an example, the predetermined speed threshold may be 3 mph and thepredetermined time period may be 5 seconds. The vehicle may travelbetween 71 and 73 miles per hour for 5 consecutive seconds. After theexpiration of the 5 consecutive seconds, the ECU may determine that thevehicle is within the steady speed range because the vehicle speed hasfluctuated relatively little over a relatively long period of time. Thisindicates that the vehicle is likely cruising along the roadway at asteady speed.

In block 206, a lookup table may be stored in the memory. The lookuptable may map efficient vehicle speeds to roadway speed limits andvehicle loads. In that regard, the ECU may determine a speed limit of acurrent roadway and a current load of the vehicle. The ECU may comparethe speed limit and the current load to the lookup table to determineone or more efficient vehicle speeds that correspond to the speed limitand current load. The one or more efficient vehicle speeds maycorrespond to vehicle speeds that are acceptable for the given speedlimit and that result in the power source being relatively energyefficient (i.e., the power source uses less energy to move the vehicleat an efficient speed than at other speeds).

In some embodiments, the lookup table may be created by the vehiclemanufacturer and stored in the memory prior to distribution of thevehicle. In some embodiments, the lookup table may be created by the ECUas the vehicle is being driven. For example, the ECU may determineefficiency of the power source at various speeds and vehicle loads andstore the results. The ECU may populate the lookup table with thespeeds, the efficiency, and the vehicle loads. In some embodiments, thelookup table may be created by the vehicle manufacturer and updated bythe ECU as the vehicle is driven.

In block 208, the ECU may determine a current load of the vehicle basedon the detected or received data. For example, the current load of thevehicle may be based on load data including one or more of a grade of acurrent roadway, a total weight or mass of the vehicle, and altitude ofthe current roadway, a velocity of a headwind or a tailwind, a currentambient temperature outside of the vehicle, or the like.

The load data may be detected by various sensors of the vehicle, such asa grade sensor or a mass sensor, may be received from surroundingvehicles or the cloud via a network access device, or may be based on acombination of detected and received data.

In block 210, the ECU may determine a current efficiency of the vehicle.For example, the ECU may analyze an amount of power or energy utilizedto move the vehicle a certain distance. The amount of power or energymay correspond to an amount of fuel burned by an engine, an amount ofelectrical energy utilized by a motor-generator, or the like. Forexample, the current efficiency of the vehicle may be measured in milesper gallon, miles per kilowatt-hour, or the like.

In block 212, the ECU may update the lookup table with the currentefficiency of the vehicle along with the current speed and a load of thevehicle. In that regard, the accuracy of the lookup table may becontinuously improved by updating the lookup table with newly detectedand determined data. This may be beneficial because the associationbetween efficiency, speeds, and vehicle loads may change over time forvarious reasons. For example, efficient speeds of a vehicle may changefor a given load if new tires are installed on the vehicle, if an engineis newly tuned up, or the like.

In block 214, the ECU may determine an upper threshold speed and a lowerthreshold speed that are acceptable for the current speed limit of theroadway. The upper threshold speed and the lower threshold speed maycorrespond to speeds that are relatively close to the speed limit andthat are considered safe and legal. In some embodiments, the upperthreshold speed and the lower threshold speed may each be apredetermined speed, such as 3 mph or 5 mph, above or below a currentspeed limit. For example, the current speed limit may be 70 mph and thepredetermined speed may be 3 mph. In this example, the upper thresholdspeed may be 73 mph and the lower threshold speed may be 67 mph.

In some embodiments the upper threshold speed and threshold speed may bea predetermined percentage above or below a current speed limit. Forexample, the predetermined percentage may be 10 percent (10%) and thecurrent speed limit maybe 50 mph. In this example, the upper thresholdspeed may be 55 mph and the lower threshold speed maybe 45 mph. In someembodiments, the upper threshold speed may be a first speed orpercentage above the speed limit and the lower threshold speed may be asecond speed or percentage below the speed limit. For example, the upperthreshold speed may be 3 miles per hour above the speed limit and thelower threshold speed may be 8 miles per hour below the speed limit.

In some embodiments, the upper threshold speed and the lower thresholdspeed may be determined based on minimum and maximum speed limits on thecurrent roadway. For example, on a given highway, a minimum allowablespeed may be 55 mph and the speed limit may be 70 mph. In this example,the upper threshold speed may be 70 mph and the lower threshold speedmay be 55 mph.

In block 216, the ECU may determine one or more efficient vehicle speedsbased on the current speed limit, the vehicle load, and the upper andlower threshold speeds. As mentioned above, the efficient vehicle speedsmay correspond to speeds at which the power source of the vehicle ismore energy-efficient than non-efficient vehicle speeds. Each of theefficient vehicle speeds determined by the ECU may be between the upperthreshold speed and the lower threshold speed, either inclusive of thethreshold speeds or non-inclusive of the threshold speeds.

In some embodiments, the upper threshold speed may exceed the speedlimit by a nominal amount. In these embodiments, the ECU may control theoutput device to indicate that any efficient vehicle speeds over thespeed limit may not be recommended in some situations. In any situation,the ECU will not output any efficient vehicle speeds that present anygreater risk than the given speed limit.

In some embodiments, the ECU may determine the one or more efficientvehicle speeds by comparing the current speed limit and the vehicle loadto the lookup table stored in the memory. For example, the ECU maycompare the current speed limit and the vehicle load to the lookup tableand determine all efficient speeds that are between the upper thresholdspeed and the lower threshold speed. In some embodiments, the ECU mayalso or instead calculate one or more efficient vehicle speed based onthe current speed limit and the vehicle load rather than access thelookup table.

In block 218, the ECU may calculate an energy differential between thecurrent vehicle speed and each of the efficient vehicle speedsdetermined in block 216. The energy differential may correspond to adifference between a current efficiency of the power source and apotential efficiency of the power source at each of the one or moreefficient vehicle speeds.

For example, the power source may include an engine that converts fuelinto mechanical energy. The ECU may calculate or otherwise predict apotential efficiency of the engine at each of the efficient vehiclespeeds based on the vehicle load and the efficient vehicle speed. Insome embodiments, the lookup table may include such potentialefficiencies or the ECU may calculate the potential efficiencies. Afterdetermining the potential efficiencies at the efficient vehicle speeds,the ECU may determine the difference between the current efficiency andthe potential efficiencies.

In block 220, the ECU may determine an amount of energy that the vehiclewill expand to reach each of the multiple efficient vehicle speeds. TheECU may further determine a distance at which the vehicle can travel ator near the speed limit before a reduction in speed is required (such asdue to a reduction in the speed limit or the vehicle taking an exit).For example, the distance may be determined based on a known orpredicted route of the vehicle.

In order to determine the amount of energy required to reach themultiple efficient speeds, the ECU may first determine a difference inspeed between the current speed and each of the efficient vehiclespeeds. The ECU may then determine an amount of energy required for thevehicle to change speeds to each of the efficient vehicle speeds.

If an efficient vehicle speed is less than the current speed and thevehicle is capable of recovering energy during a deceleration then theamount of energy required to reach the efficient vehicle speed may benegative. A negative amount of energy may correspond to a gain in totalenergy of the vehicle. On the other hand, if an efficient vehicle speedis greater than the current speed, the amount of energy required toreach the efficient vehicle speed may be positive. A positive amount ofenergy indicates that the vehicle will use energy to reach the efficientvehicle speed.

The ECU may determine or predict the distance at which the vehicle cantravel at or near the speed limit in multiple ways. For example, the ECUmay compare the current location of the vehicle to map data stored inthe memory or retrieved via the network access device to determine adistance at which the current speed limit remains without change. TheECU may also compare a route of the vehicle to the map data to determineif or when the vehicle will turn on to another road having a differentspeed limit. In some embodiments, the ECU may know or predict a route ofthe vehicle and may compare the known or predicted route to the mapdata.

In block 222, the ECU may calculate a total efficiency of each of themultiple efficient vehicle speeds. The ECU may calculate this totalefficiency based on the efficiency differential determined in block 218along with the amount of energy required to reach each of the multipleefficient vehicle speeds and the distance at which the vehicle cantravel at or near the speed limit that was determined in block 220.

For example, if a relatively large amount of energy is required to reachan efficient vehicle speed and the vehicle may only travel at theefficient vehicle speed for a relatively short period of time then thetotal efficiency for traveling at the efficient vehicle speed may berelatively low. Conversely, if a relatively small amount of energy isrequired to reach an efficient vehicle speed and the vehicle is capableof traveling at the efficient vehicle speed for a relatively long periodof time then the total efficiency for traveling at the efficient vehiclespeed may be relatively high.

As another example, if a relatively large amount of energy is requiredto reach an efficient vehicle speed and the energy differential for theefficient vehicle speed is relatively low then the total efficiency fortraveling at the efficient vehicle speed may be relatively low.Conversely, if a relatively small amount of energy is required to reachan efficient vehicle speed and the energy differential for the efficientvehicle speed is relatively high then the total efficiency for travelingat the efficient vehicle speed may be relatively high.

In block 224, the ECU may compare the total efficiency of each of theefficient vehicle speeds. The ECU may eliminate one or more of theefficient vehicle speeds having a relatively low total efficiency. Forexample, a speed limit may be 70 mph and the corresponding efficientvehicle speeds may be 65 mph, 69 mph, and 72 mph. The ECU may determinethat the vehicle will save half a gallon of gasoline if it travels at 65mph, will save ⅗ of a gallon of gasoline if it travels at 69 mph, andwill not save any gasoline if it travels at 72 mph. In this example, theECU may eliminate 72 mph as an efficient vehicle speed because it willnot save any gasoline.

In block 226, the ECU may rank the one or more efficient vehicle speeds.For example, the ECU may rank the one or more efficient vehicle speedsbased on the energy differential determined in block 218, based on thetotal efficiency determined in block 222, or based on a combination ofthe energy differential and the total efficiency. The ECU may rank theefficient vehicle speeds based on an order of efficiency. For example,an efficient vehicle speed having a greater energy differential or agreater total efficiency may be ranked higher than an efficient vehiclespeed having a smaller energy differential or total efficiency.

In block 228, the ECU may control an output device to output theefficient vehicle speeds and the corresponding energy differential or atotal efficiency when the vehicle is within the steady speed range(i.e., in a cruising state). In some embodiments, the ECU may onlyoutput the efficient vehicle speeds when the vehicle is not alreadytraveling at an efficient vehicle speed. In some embodiments, if thevehicle is already traveling at an efficient vehicle speed then the ECUmay control the output device to output data indicating that the vehicleis traveling at an efficient vehicle speed.

A driver may view the efficient vehicle speeds and corresponding energydifferential or total efficiency and may decide to drive the vehicle atone of the efficient vehicle speeds. In some embodiments, the ECU maycontrol the output device to output data verifying that the vehicle isbeing driven at one of the efficient vehicle speeds when the driver isdriving at the one of the efficient vehicle speeds. In some embodiments,the ECU may control the output device to output the corresponding energydifferential or total efficiency after a period of time has elapsedsince outputting the efficient vehicle speeds without the vehicletraveling at one of the efficient vehicle speeds.

In some embodiments, the vehicle may be autonomous. In that regard, theECU may control the power source to move the vehicle at one of theefficient vehicle speeds, such as the most efficient vehicle speed,without verification from a user or driver.

In some embodiments, the ECU may control the network access device tooutput the efficient vehicle speeds, or the current speed of thevehicle, to nearby vehicles in block 230. By outputting the efficientvehicle speeds or the current speed, the ECU may identify the current orfuture speed of the vehicle to other vehicles. In that regard, thenearby vehicles may be aware of the speed at which the current vehicleis traveling. The ECU may transmit this information to promote awarenessor reasoning behind the current vehicle speed. In some embodiments,another vehicle with a similar efficiency profile may caravan with thepresent vehicle to improve traffic flow and fuel efficiency based on thetransmitted speed.

In block 232, the ECU may control the output device to cease outputtingthe efficient vehicle speed when an upcoming grade of the currentroadway varies from the current grade by more than a predetermined gradethreshold. The predetermined grade threshold may correspond to a changeof grade sufficiently great to change the vehicle load enough that theefficient vehicle speed calculation may change. For example, anefficient speed for a grade of 0% may be 70 mph. The vehicle may beapproaching a hill at which the grade becomes 5%. The grade change of 5%may be sufficiently large that 70 mph is no longer an efficient speedfor the vehicle. In that regard, the ECU may control the output deviceto cease outputting the efficient vehicle speed as the vehicle isapproaching the hill.

In some embodiments, the ECU may calculate or determine one or more newefficient vehicle speeds for the upcoming hill based on the new loadapplied by the 5% grade. In some embodiments, the ECU may control thevehicle to change to one of the new efficient vehicle speeds when thevehicle reaches the start of the hill.

In block 234, the driver of the vehicle may occasionally request thatthe vehicle operate in a cruise control mode. A cruise control modecorresponds to a mode in which the ECU controls the vehicle to operateat a steady speed. In block 236, if the driver has requested the cruisecontrol mode, the ECU may control the vehicle to operate at one of theefficient vehicle speeds.

In some embodiments, the ECU may be capable of calculating anenergy-efficient acceleration pattern from a current speed of thevehicle to a target vehicle speed, such as one of the efficient vehiclespeeds. In that regard, the ECU may control the power source toaccelerate the vehicle to the target speed using the efficientacceleration pattern. For example, the ECU may determine the one or moreefficient vehicle speeds and output the one or more efficient vehiclespeeds via the output device.

The user may select one of the one or more efficient vehicle speedsusing an input device. In some embodiments the ECU may control thevehicle to accelerate to the selected efficient vehicle speed using theenergy-efficient acceleration pattern in response to the user selectionof the efficient vehicle speed. In some embodiments, the user mayprovide input via an input device requesting the ECU to accelerate tothe efficient vehicle speed and the ECU may control the vehicle toaccelerate to the selected efficient vehicle speed in response to thisuser input.

Referring now to FIGS. 3A and 3B, a method 300 for controlling avehicle, such as the vehicle 100 of FIG. 1, to accelerate efficiently isshown. In block 200, various components of the vehicle may detect andstore previous accelerations data. The previous acceleration data may bedetected and stored as the vehicle is driven. In some embodiments, atleast some of the previous acceleration data may be detected and storedby the vehicle manufacturer during vehicle testing cycles. The previousacceleration data may include a plurality of final vehicle speeds,starting locations at which accelerations began, and acceleratedlocations at which the vehicle reaches the final vehicle speed. Each ofthe final vehicle speeds corresponds to a final speed of the vehicleafter the vehicle has completed an acceleration. In some embodiments,the previous acceleration data may include additional data such as loadsof the vehicle and corresponding efficiency of each of theaccelerations.

In block 304, various components of the vehicle may detect or receivedata including a current speed of the vehicle, image data correspondingto a roadway of the vehicle, location data corresponding to a currentlocation of the vehicle, and load data corresponding to a load of thevehicle. The load data may include data corresponding to the currentload of the vehicle as well as to a potential future load of thevehicle. For example, the vehicle may be traveling along a city roadhaving a relatively low-grade (such as 1% or 2%), and a route mayindicate that the vehicle will take an upcoming highway on-ramp. The ECUmay determine that the highway on-ramp has a relatively large grade(such as 5%). In that regard, the load data may include the grade of thecurrent roadway and the grade of the upcoming highway on-ramp.

In block 306, the ECU may predict an upcoming acceleration of thevehicle based on detected or received data. For example, the ECU maypredict that an acceleration is forthcoming when the camera detect imagedata corresponding to a speed limit sign that indicates that a currentspeed limit of the roadway will increase. Similarly, the ECU may comparethe current location of the vehicle to the stored starting locations atwhich the accelerations began. If the current location of the vehicle isapproaching one of the stored starting locations then the ECU maydetermine that the vehicle will accelerate when it reaches the upcomingstored starting location.

As yet another example, the ECU may know or predict a route of thevehicle. The ECU may further determine, based on the known or predictedroute and the current location of the vehicle, that the vehicle will beentering a highway on-ramp or making a turn and will thus accelerate onthe on-ramp or accelerate or decelerate after the turn. A similar tacticmay be used to determine when a speed limit of a current roadwaychanges.

In some embodiments, the ECU may prioritize predicted accelerations thathave been previously performed in a relatively inefficient manner. Forexample, the ECU may only perform the remaining steps of the method 300if previously-detected data indicates that the predicted accelerationhas been performed relatively inefficiently by the driver. For example,the ECU may be aware of three vehicle accelerations. In a firstacceleration, the ECU may determine that a maximum efficient control canonly increase efficiency by 10%; in a second, the ECU may determine thatthe efficiency can be increased by 5%; in a third, the ECU may determinethat the efficiency can be increased by 50%.

In some embodiments, the ECU will only perform the remaining steps ofthe method 300 for the third acceleration. In some embodiments, the ECUmay perform the remaining steps of the method 300 if the efficiency canbe increased by an efficiency threshold that corresponds to anefficiency that may provide sufficient energy savings to the driver. Forexample, the efficiency threshold may be 25%, 50%, or the like. Stateddifferently, the ECU may control the power source to accelerate thevehicle when an efficiency of the energy-efficient acceleration patternis at least an energy threshold percentage above a previous efficiencyof a previously performed acceleration pattern for a same location.

In some embodiments, the ECU may only perform the remaining steps of themethod 300 if a user of the vehicle has requested accelerationassistance via an input device.

In some embodiments, the method 300 may be applied only to accelerationsto target speeds that are greater than the current speed of the vehicle.Accordingly and in block 308, the ECU may determine a target vehiclespeed that is greater than the current speed of the vehicle. The targetvehicle speed may correspond to a final speed of the vehicle after anupcoming acceleration has been performed.

The target vehicle speed may be determined based on detected data,received data, data stored in the memory, or the like. For example, thecamera may detect data corresponding to a speed limit sign and the ECUmay determine that the target vehicle speed is the new speed limit. Asanother example, if the current location of the vehicle is approachingone of the stored starting locations, then the ECU may determine thatthe target vehicle speed is the stored final vehicle speed thatcorresponds to the upcoming stored starting location.

As yet another example, the ECU may determine one or more efficientvehicle speeds for a current or upcoming speed limit, and may furtherdetermine the target vehicle speed based on the one or more efficientvehicle speed.

In block 310, the ECU may control an output device to output dataindicating the prediction of the upcoming acceleration and thedetermined target vehicle speed. In some embodiments, the ECU mayfurther control the output device to output data requesting aconfirmation of the upcoming acceleration and the target vehicle speed.For example, the output device may output information such as “it ispredicted that you will accelerate onto the 405 on-ramp in a quarter ofa mile. Would you like for the acceleration to be handled autonomously?”

In some embodiments, if the ECU determines multiple efficient vehiclespeeds in block 308, then the ECU may control the output device tooutput the multiple efficient vehicle speeds and request a selection ofone of the multiple efficient vehicle speeds from a driver or user ofthe vehicle. In some embodiments, the ECU may also output energydifferentials or total amounts of energy expected to be used for each ofthe multiple efficient vehicle speeds to provide incentive for thedriver or user to select one of the efficient vehicle speeds.

If the ECU controls the output device to output the confirmation requestthen the ECU may receive the confirmation from the user via an inputdevice in block 312. In some embodiments, the confirmation may alsoinclude a selection of one of the multiple efficient vehicle speeds.

In some embodiments, if the driver takes longer than a predeterminedtime period to respond to the confirmation request, then the system maytime out. In some embodiments, the system may instead proceed withoutconfirmation if the driver has previously requested accelerationassistance.

In block 314, the ECU may determine a starting location at which thevehicle should begin accelerating. The ECU may also or instead determinean accelerated location at which the vehicle should reach or betraveling at the target vehicle speed. The ECU may determine thestarting location based on detected or received data. For example, theECU may compare the current location of the vehicle to the previouslystored starting locations and may determine that the previously storedstarting location is the starting location for the forthcomingacceleration. As another example, the ECU may analyze detected imagedata to determine a location of a speed limit sign with an increasedspeed limit, and may determine that the starting location is thelocation of the speed limit sign.

The ECU may also determine the accelerated location based on detected orreceived data. For example, the ECU may analyze the detected image datato determine a location of a speed limit sign with an increased speedlimit, and may determine that the accelerated location is the locationof the speed limit sign. As another example, the ECU may compare thecurrent location of the vehicle to the data stored in the memory and maydetermine that a previously stored accelerated location which thevehicle is approaching is the accelerated location for the forthcomingacceleration.

In some embodiments, the ECU may determine the starting location basedon the accelerated location. For example, the ECU may determine that thevehicle is approaching a highway on-ramp and may determine that theaccelerated location is the location at which the vehicle merges ontothe highway. The ECU may determine that the starting location is apredetermined distance before the accelerated location, such as 100yards, 200 yards, or the like. The predetermined distance may correspondto a distance which provides sufficient time for the power source toefficiently accelerate to the target vehicle speed. In some embodiments,the predetermined distance may vary based on the current vehicle speedand the target vehicle speed such that the predetermined distance isgreater for greater current or target vehicle speeds.

In block 316, the ECU may predict future energy usage of the powersource after the power source accelerates to the target vehicle speed.The prediction of the future energy usage may be based on informationsuch as the target vehicle speed, the distance at which the vehicle willtravel at the target vehicle speed, and load information including acurrent and future grade of traveled roadways. The predicted futureenergy usage may include information such as an amount of fuel orelectrical energy that will be used until the vehicle decelerates,whether the motor-generator will be capable of generating electricityduring any forthcoming portion of the route, or the like.

In block 318, the ECU may calculate an energy-efficient accelerationpattern to accelerate the vehicle to the target speed. Theenergy-efficient acceleration pattern may correspond to an accelerationpattern that provides greater energy efficiency than other accelerationpatterns. In that regard, the vehicle may conserve fuel or electricalenergy by accelerating using the energy-efficient acceleration patternrather than accelerating using a different acceleration pattern.

The ECU may calculate the energy-efficient acceleration patterns basedon various information such as one or more of the current speed of thevehicle, the target speed of the vehicle, the load of the vehicle (acurrent grade of a roadway and a forthcoming grade of an upcomingportion of the roadway), the predicted future energy usage, a distanceat which the vehicle will travel at the target vehicle speed, a currentstate of charge (SOC) of the battery or fuel level, current trafficconditions, and a distance between the starting location of theacceleration and the accelerated location.

The ECU may utilize the current speed of the vehicle and the targetspeed of the vehicle to determine an amount of acceleration required toreach the target speed from the current speed. The load data may includeinformation such as a mass of the vehicle, an amount of headwind ortailwind, an altitude of the roadway, an amount of traffic on theroadway or the accelerated location, a current grade of the roadway, anda future grade of the roadway.

The grade information may be utilized in the calculation because thepower source may be more efficient at a given power output level whenthe vehicle is under a first load, and may be more efficient at anotherpower output level when the vehicle is under a different load.

The energy-efficient acceleration patterns may further includeinformation such as an amount of power requested from an engine and anamount of power requested from a motor-generator. For example, it may bebeneficial in some accelerations to utilize only power from themotor-generator, it may be beneficial to utilize only power from theengine, or it may be beneficial to use a blend of power from the engineand the motor-generator. In that regard, the potential future energyusage may affect the decision of whether to utilize power from themotor-generator, the engine, or a blend of power.

For example, if the potential future energy usage indicates that themotor-generator will be capable of generating electricity shortly afterthe acceleration then the ECU may control the motor-generator togenerate a majority of the power for the acceleration. Similarly, if thetarget vehicle speed is a cruising speed at which the motor-generatormay provide all power then the acceleration may be more efficient if theengine is controlled to generate a majority of the power for theacceleration. Such control may retain sufficient SOC for the battery andmotor-generator to propel the vehicle for the duration of the cruisingspeed.

The distance at which the vehicle will travel at the target vehiclespeed may affect the target speed or the energy-efficient accelerationpattern. For example, if the vehicle is approaching a highway on-rampbut will only travel on the highway for half of a mile then the ECU mayset the target vehicle speed to be lower than if the vehicle will travelon the highway for many miles. This is because the extra energy used toaccelerate the vehicle to the higher-speed may be wasted because thevehicle will decelerate shortly after reaching the target speed.

In block 320, the ECU may take control of the power source from a driverof the vehicle when the vehicle reaches the starting location of theacceleration. In some embodiments, the ECU may take control of the powersource from the driver at an earlier point in time, such as when thedriver confirms the forthcoming acceleration. The ECU may provide anoption at any point in time for the driver to cancel the autonomouscontrol of the power source. For example, the user may cancel theautonomous control via the input device, by depressing a brake pedal, orthe like.

In some embodiments, the vehicle may be operating in an autonomouscruise control. In that regard, the ECU may already have control of thepower source of the vehicle and need not take control from a driver.

In block 322, the ECU may control the power source to accelerate thevehicle to the target speed using the energy-efficient accelerationpattern determined in block 318. In some embodiments, if the driverfails to confirm the acceleration assistance request until the startinglocation has been passed, the ECU may update the calculation based onthe current location to determine an updated efficient accelerationpattern. The ECU may then take control of the power source andimplemented the updated efficient acceleration pattern upon receivingthe confirmation at the new starting location.

In block 324, the ECU may relinquish control of the power source whenthe current speed reaches the target speed. In some embodiments, the ECUmay first output data indicating that control of the power source willbe relinquished shortly and requesting confirmation from the driver thatthe driver wishes to take control of the power source. In someembodiments, the driver may indicate a preference for the ECU tocontinue controlling the power source, i.e., for the ECU to control thevehicle in a cruise control or autonomous mode. In that regard, the ECUmay continue controlling the power source after the vehicle reaches thetarget vehicle speed.

In block 326, the ECU may determine the efficiency of the acceleration.In some embodiments, the ECU may determine the efficiency of theacceleration during the acceleration and, in some embodiments, the ECUmay determine the efficiency of the acceleration after the accelerationis complete. The ECU may determine the efficiency of the acceleration bydetermining an amount of energy (including fuel and electrical energy)used during the acceleration, and comparing the used amount of energy tothe acceleration pattern. In some embodiments, the ECU may determine theefficiency of the acceleration using any other available method.

In block 328, the ECU may update the calculation of the energy-efficientacceleration pattern if the efficiency determined in block 326 isdifferent than the expected efficiency. For example, the calculation maybe based on a set of data including previously-detected efficiency data.In some embodiments, the ECU may update the calculation by updating theset of data upon which the calculation is based. In some embodiments,the ECU may update or adjust the calculation (or implement thecalculation in a different manner) by altering the acceleration patternmid-acceleration. For example, if the motor-generator is utilizing moreelectrical energy than anticipated, the ECU may update the calculationby controlling the motor-generator to generate less power.

Referring now to FIGS. 1 and 4, the vehicle 100 may be traveling along aroad system 400 and may utilize the method 200 of FIGS. 2A and 2B andthe method 300 of FIGS. 3A and 3B. The vehicle 100 may initially betraveling on a city road 402 in a direction 404. The city road 402 mayhave a speed limit of 45 mph. The ECU 102 of the vehicle 100 may predictthat the vehicle will take a highway on-ramp 406 to enter a highway 408.The ECU 102 may further determine that the speed limit of the highway408 is 60 mph. The ECU may determine that the starting location of theacceleration is an entrance 410 of the on-ramp 406 and the acceleratedlocation is the exit 412 of the on-ramp 406.

The ECU 102 may control the output device 138 to output data indicatingthat the vehicle 100 is predicted to accelerate to 60 mph starting atthe entrance 410 to the highway on-ramp 406. The ECU 102 may furthercontrol the output device 138 to request confirmation from the driverthat the ECU 102 is to control the acceleration. The input device mayreceive such verification from the driver.

The ECU 102 may determine the current vehicle speed and the load of thevehicle (including a grade of the on-ramp 406) based on detected orreceived data. Based on the current vehicle speed, the load of thevehicle, the target speed of 60 mph, and the distance between theentrance 410 and the exit 412, the ECU 102 may calculate anenergy-efficient acceleration pattern. As the vehicle 100 approaches theentrance 410, the ECU 102 may take control of the power source 111 fromthe driver and may control the vehicle 100 to accelerate to 60 mph usingthe energy-efficient acceleration pattern.

When the vehicle 100 reaches the exit 412 of the on-ramp 406, the ECU102 may relinquish control of the power source 111 to the driver. TheECU 102 may then compare the current speed limit of 60 mph and thecurrent vehicle load to a lookup table to retrieve one or more efficientvehicle speeds. The ECU 102 may determine that a first efficient vehiclespeed is 57 mph and a second efficient vehicle speed is 62 mph. In someembodiments, the ECU may determine the efficient vehicle speeds prior tocalculating the efficient acceleration pattern and may select one of theefficient vehicle speeds (or request the driver to select one of theefficient vehicle speeds) as the target vehicle speed for theacceleration along the on-ramp 406.

The ECU 102 may then calculate and control the output device 138 tooutput an energy differential for each of the efficient vehicle speeds.The driver may view the efficient vehicle speeds and may control thepower source 111 to move the vehicle at a selected efficient vehiclespeed.

The speed limit of the highway 408 may increase to 70 mph at a location414. The camera 120 may detect a speed limit sign 416 as the vehicle 100approaches the speed limit sign 416. The ECU 102 may output dataindicating that the ECU 102 predicts that the vehicle will accelerate to70 mph and requesting verification of the acceleration from the driver.Upon receiving the verification, the ECU 102 may utilize the lookuptable to determine one or more efficient vehicle speed for the portionof the highway 408 after the speed limit sign 416. For example, the ECU102 may determine that 67 mph and 72 mph are efficient speeds. The ECU102 may further predict that the vehicle 100 will take an off-ramp 418to another city road 420 a relatively short distance after theacceleration to 70 mph. Because the vehicle 100 will only travel on thehighway 408 at 70 mph for a relatively short period of time, the ECU 102may eliminate 72 mph from the efficient speed list.

As the vehicle 100 approaches the location 414, the ECU 102 may takecontrol of the power source 111 and control the power source 111 toaccelerate the vehicle to 67 mph. The ECU 102 may then relinquishcontrol of the power source 111 back to the driver or, based on a driverrequest, may control the vehicle to remain at 67 mph in an autonomous orcruise control mode.

Where used throughout the specification and the claims, “at least one ofA or B” includes “A” only, “B” only, or “A and B.” Exemplary embodimentsof the methods/systems have been disclosed in an illustrative style.Accordingly, the terminology employed throughout should be read in anon-limiting manner. Although minor modifications to the teachingsherein will occur to those well versed in the art, it shall beunderstood that what is intended to be circumscribed within the scope ofthe patent warranted hereon are all such embodiments that reasonablyfall within the scope of the advancement to the art hereby contributed,and that that scope shall not be restricted, except in light of theappended claims and their equivalents.

What is claimed is:
 1. A system for controlling a vehicle to accelerateefficiently, comprising: a power source configured to generate power topropel the vehicle; a speed sensor configured to detect a current speedof the vehicle; a camera configured to detect image data correspondingto a current roadway; a global positioning system (GPS) sensorconfigured to detect location data corresponding to a current locationof the vehicle; and an electronic control unit (ECU) coupled to thepower source, the speed sensor, the camera, and the GPS sensor, andconfigured to: determine a target vehicle speed that is greater than thecurrent speed of the vehicle based on at least one of the image data orthe location data, calculate an energy-efficient acceleration pattern toaccelerate the vehicle from the current speed to the target vehiclespeed based on a goal to minimize energy usage of the power source, andcontrol the power source to accelerate the vehicle from the currentspeed to the target vehicle speed using the energy-efficientacceleration pattern.
 2. The system of claim 1 further comprising a loadsensor configured to detect load data corresponding to a current load ofthe vehicle, wherein the ECU is further configured to determine thecurrent load of the vehicle based on the load data and to calculate theenergy-efficient acceleration pattern based on the current load of thevehicle.
 3. The system of claim 2 wherein the current load of thevehicle is based on at least one of a grade of the current roadway, atotal mass of the vehicle, an altitude of the current roadway, avelocity of a headwind or a tailwind, or a current ambient temperatureoutside of the vehicle.
 4. The system of claim 1 further comprising: anoutput device configured to output data indicating that the vehicle ispredicted to accelerate to the target vehicle speed and requesting aconfirmation that the vehicle is to accelerate to the target vehiclespeed; and an input device configured to receive the confirmation thatthe vehicle is to accelerate to the target vehicle speed, theconfirmation corresponding to a request for the ECU to control the powersource to accelerate the vehicle to the target vehicle speed, whereinthe ECU is configured to control the power source to accelerate thevehicle to the target vehicle speed after the input device receives theconfirmation.
 5. The system of claim 1 wherein the ECU is configured totake control of the power source from a driver of the vehicle toaccelerate the vehicle to the target vehicle speed, and to relinquishthe control of the power source to the driver of the vehicle when thecurrent speed of the vehicle equals the target vehicle speed.
 6. Thesystem of claim 1 further comprising a memory configured to storeprevious acceleration data including a plurality of final vehicle speedsand corresponding starting locations at which previous accelerations tothe plurality of final vehicle speeds began, wherein the ECU is furtherconfigured to: determine the target vehicle speed by comparing thecurrent location of the vehicle to the starting locations of theprevious acceleration data; and control the power source to acceleratethe vehicle from the current speed to the target vehicle speed beginningwhen the current location of the vehicle reaches one of the startinglocations of the previous acceleration data.
 7. The system of claim 1wherein the ECU is further configured to determine a starting locationat which the vehicle should start accelerating to the target vehiclespeed based on at least one of a known vehicle route, a predictedvehicle route, or a highway on-ramp or a speed limit sign included inthe image data.
 8. The system of claim 7 wherein the ECU is furtherconfigured to: determine an accelerated location at which the vehicleshould be traveling at the target vehicle speed; and determine theenergy-efficient acceleration pattern based on the current speed of thevehicle and a distance between the starting location and the acceleratedlocation.
 9. The system of claim 1 wherein the ECU is further configuredto: determine a current speed limit of the current roadway based on atleast one of the image data or the location data; determine an efficientspeed of the vehicle based on the current speed limit of the currentroadway; and determine the target vehicle speed to be equal to theefficient speed of the vehicle.
 10. The system of claim 1 wherein theECU is further configured to predict future energy usage of the powersource after the power source accelerates to the target vehicle speedand to calculate the energy-efficient acceleration pattern based on thepredicted energy usage.
 11. The system of claim 1 wherein the ECU isfurther configured to control the power source to accelerate the vehiclewhen an efficiency of the energy-efficient acceleration pattern is atleast an energy threshold percentage above a previous efficiency of apreviously performed acceleration pattern for a same location.
 12. Asystem for controlling a vehicle to accelerate efficiently, comprising:a power source configured to generate power to propel the vehicle; aspeed sensor configured to detect a current speed of the vehicle; acamera configured to detect image data corresponding to a currentroadway; a global positioning system (GPS) sensor configured to detectlocation data corresponding to a current location of the vehicle; aninput device configured to receive input data; an output deviceconfigured to output data; and an electronic control unit (ECU) coupledto the power source, the speed sensor, the camera, the GPS sensor, theinput device, and the output device, and configured to: predict that thevehicle is to accelerate to a target vehicle speed based on at least oneof the image data or the location data, control the output device tooutput data indicating the predicted acceleration, control the inputdevice to receive confirmation that the vehicle is to accelerate to thetarget vehicle speed, calculate an energy-efficient acceleration patternto accelerate the vehicle from the current speed to the target vehiclespeed based on a goal to minimize energy usage of the power source, andcontrol the power source to accelerate the vehicle from the currentspeed to the target vehicle speed using the energy-efficientacceleration pattern after the input device receives the confirmation.13. The system of claim 12 further comprising a load sensor configuredto detect load data corresponding to a current load of the vehicle andincluding at least one of a grade of the current roadway, a total massof the vehicle, an altitude of the current roadway, a velocity of aheadwind or a tailwind, or a current ambient temperature outside of thevehicle, wherein the ECU is further configured to determine the currentload of the vehicle based on the load data and to calculate theenergy-efficient acceleration pattern based on the current load of thevehicle.
 14. The system of claim 12 wherein the ECU is configured totake control of the power source from a driver of the vehicle toaccelerate the vehicle to the target vehicle speed, and to relinquishthe control of the power source to the driver of the vehicle when thecurrent speed of the vehicle equals the target vehicle speed.
 15. Thesystem of claim 12 further comprising a memory configured to storeprevious acceleration data including a plurality of final vehicle speedsand corresponding starting locations at which previous accelerations tothe plurality of final vehicle speeds began, wherein the ECU is furtherconfigured to: predict that the vehicle is to accelerate to the targetvehicle speed when the location data indicates that the current locationof the vehicle is approaching one of the starting locations; anddetermine the target vehicle speed by determining that the targetvehicle speed equals a final vehicle speed that corresponds to the oneof the starting locations.
 16. The system of claim 12 wherein the ECU isfurther configured to: determine a starting location at which thevehicle should start accelerating to the target vehicle speed based onat least one of a known vehicle route, a predicted vehicle route, or ahighway on-ramp or a speed limit sign included in the image data;determine an accelerated location at which the vehicle should betraveling at the target vehicle speed; and determine theenergy-efficient acceleration pattern based on the current speed of thevehicle and a distance between the starting location and the acceleratedlocation.
 17. A method for controlling a vehicle to accelerateefficiently, comprising: generating, by a power source, power to propelthe vehicle; detecting, by a speed sensor, a current speed of thevehicle; detecting, by a camera, image data corresponding to a currentroadway; detecting, by a global positioning system (GPS) sensor,location data corresponding to a current location of the vehicle;determining, by an electronic control unit (ECU), a target vehicle speedthat is greater than the current speed of the vehicle based on at leastone of the image data or the location data; calculating, by the ECU, anenergy-efficient acceleration pattern to accelerate the vehicle from thecurrent speed to the target vehicle speed based on a goal to minimizeenergy usage of the power source; and controlling, by the ECU, the powersource to accelerate the vehicle from the current speed to the targetvehicle speed using the energy-efficient acceleration pattern.
 18. Themethod of claim 17 further comprising: outputting, by an output device,data indicating that the vehicle is predicted to accelerate to thetarget vehicle speed and requesting a confirmation that the vehicle isto accelerate to the target vehicle speed; receiving, by an inputdevice, the confirmation that the vehicle is to accelerate to the targetvehicle speed, the confirmation corresponding to a request for the ECUto control the power source to accelerate the vehicle to the targetvehicle speed; determining, by the ECU, a starting location at which thevehicle should start accelerating to the target vehicle speed; takingover, by the ECU, control of the power source from a driver of thevehicle to accelerate the vehicle to the target vehicle speed when thevehicle reaches the starting location; and relinquishing, by the ECU,control of the power source to the driver of the vehicle when thecurrent speed of the vehicle reaches the target vehicle speed.
 19. Themethod of claim 17 further comprising: storing, in a memory, previousacceleration data including a plurality of final vehicle speeds andcorresponding starting locations at which previous accelerations to theplurality of final vehicle speeds began; determining, by the ECU, thetarget vehicle speed by comparing the current location of the vehicle tothe starting locations of the previous acceleration data; and whereincontrolling the power source to accelerate the vehicle from the currentspeed to the target vehicle speed begins when the current location ofthe vehicle reaches one of the starting locations of the previousacceleration data.
 20. The method of claim 17 further comprising:determining, by the ECU, a current speed limit of the current roadwaybased on at least one of the image data or the location data;determining, by the ECU, an efficient speed of the vehicle based on thecurrent speed limit of the current roadway; and determining, by the ECU,the target vehicle speed to be equal to the efficient speed of thevehicle.